Risk of a first community-acquired spontaneous bacterial peritonitis in cirrhotics with low ascitic fluid protein levels

Diagnosis, treatment and prevention of spontaneous bacterial peritonitis

Spontaneous bacterial peritonitis (SBP) is a frequent complication in cirrhotic patients with ascites. Diagnosis of SBP is established by a polymorphonuclear cell count in ascitic fluid > or =250 cells/mm(3). The organism responsible for the infection is isolated in 60-70% of the cases. The remaining cases are considered to have a variant of SBP (culture-negative SBP) and are treated in the same way as those with a positive culture. The SBP resolution rate ranges between 70 and 90%, and hospital survival between 50 and 70%. An early diagnosis and the use of a more adequate antibiotic therapy are the most probable reasons for the improvement in prognosis for SBP in recent decades. Despite the resolution of the infection, SBP may trigger severe complications such as renal impairment, gastrointestinal bleeding and accentuation of hepatic insufficiency which are responsible for the associated mortality. Patients recovering from an episode of SBP should be considered as potential candidates for liver transplantation.

Portal hypertension

Cirrhosis represents the end-stage of any chronic liver disease. Two major syndromes result from cirrhosis-portal hypertension and hepatic insufficiency. Additionally, vasodilatation and the hyperdynamic circulation are hemodynamic abnormalities typical of cirrhosis and portal hypertension. Complications of cirrhosis occur as a consequence of a combination of these factors. Gastroesophageal varices result almost solely from portal hypertension, although the hyperdynamic circulation contributes to variceal growth and hemorrhage. Ascites results from sinusoidal hypertension and sodium retention, which is, in turn, secondary to vasodilatation and activation of neurohumoral systems. Hepatorenal syndrome also results from severe peripheral vasodilatation that leads to renal vasoconstriction. Another complication of cirrhosis, portosystemic encephalopathy, is a consequence of both portal hypertension (shunting of blood through portosystemic collaterals) and hepatic insufficiency. In this article, recent advances in pathophysiology and management of the complications of cirrhosis and portal hypertension are reviewed.

Spontaneous Bacterial Peritonitis

A suspicion, even if low, of spontaneous bacterial peritonitis (SBP) should prompt a diagnostic paracentesis to be performed on presentation. Empiric antibiotic therapy with a third-generation cephalosporin should commence upon demonstration of over 250 granulocytes/mm(3) in ascitic fluid. Treatment for 5 days in uncomplicated SBP is sufficient; persistent symptoms and/or ascites fluid showing persistent granulocytosis (over 250 cells/mm(3)) should be handled by broadening of antibiotic spectrum and searching for secondary causes of peritonitis. Antibiotic prophylaxis for cirrhotic patients with ascites and acute gastrointestinal hemorrhage and in those with a prior history of SBP is indicated.